}

  /** Returns a new builder. */
  public static <B> Builder<B> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable type-to-instance maps. Example:
   *
   * {@snippet :
   * static final ImmutableTypeToInstanceMap<Handler<?>> HANDLERS =
   *     ImmutableTypeToInstanceMap.<Handler<?>>builder()
   *         .put(new TypeToken<Handler<Foo>>() {}, new FooHandler())

Just use any kind of model, any kind of class, any kind of database that you need for your application. **FastAPI** has you covered with the dependency injection system.

## Code size { #code-size }

This example might seem verbose. Keep in mind that we are mixing security, data models, utility functions and *path operations* in the same file.

But here's the key point.

The security and dependency injection stuff is written once.

 * <p>Some uses of this class include
 *
 * <ul>
 *   <li>As a method return type, as an alternative to returning {@code null} to indicate that no
 *       value was available
 *   <li>To distinguish between "unknown" (for example, not present in a map) and "known to have no
 *       value" (present in the map, with value {@code Optional.absent()})
 *   <li>To wrap nullable references for storage in a collection that does not support {@code null}

Another easy way to get to the Javadoc is to open
[guava.dev/api](https://guava.dev/api). You can also jump right to a specific
class by appending the class name to guava.dev. For example,
[guava.dev/ImmutableList](https://guava.dev/ImmutableList)!

## Learn about Guava

-   Our users' guide, [Guava Explained]
-   [A nice collection](https://www.tfnico.com/presentations/google-guava) of

   *
   * @since 19.0
   */
  Map<Range<K>, V> asDescendingMapOfRanges();

  /**
   * Returns a view of the part of this range map that intersects with {@code range}.
   *
   * <p>For example, if {@code rangeMap} had the entries {@code [1, 5] => "foo", (6, 8) => "bar",
   * (10, ∞) => "baz"} then {@code rangeMap.subRangeMap(Range.open(3, 12))} would return a range map

 * access, the {@code ForwardingList} subclass should implement the {@code RandomAccess} interface.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingList} forward <b>indiscriminately</b> to the
 * methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change the
 * behavior of {@link #addAll}, which can lead to unexpected behavior. In this case, you should

 * the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingSortedMultiset} forward
 * <b>indiscriminately</b> to the methods of the delegate. For example, overriding {@link
 * #add(Object, int)} alone <b>will not</b> change the behavior of {@link #add(Object)}, which can
 * lead to unexpected behavior. In this case, you should override {@code add(Object)} as well,

│   └── test_main.py
```

因為這個檔案在同一個套件中，你可以使用相對匯入，從 `main` 模組（`main.py`）匯入 `app` 這個物件：

{* ../../docs_src/app_testing/app_a_py310/test_main.py hl[3] *}


...然後測試的程式碼就和先前一樣。

## 測試：進階範例 { #testing-extended-example }

現在我們延伸這個範例並加入更多細節，看看如何測試不同部分。

### 擴充的 **FastAPI** 應用檔案 { #extended-fastapi-app-file }

沿用先前相同的檔案結構：

```
.
├── app
│   ├── __init__.py
│   ├── main.py
│   └── test_main.py

Callback'in gerçek kodu, büyük ölçüde sizin API uygulamanıza bağlıdır.

Ve bir uygulamadan diğerine oldukça değişebilir.

Sadece bir-iki satır kod bile olabilir, örneğin:

```Python
callback_url = "https://example.com/api/v1/invoices/events/"
httpx.post(callback_url, json={"description": "Invoice paid", "paid": True})
```

│   └── test_main.py
```

因为这文件在同一个包中，所以你可以通过相对导入从 `main` 模块（`main.py`）导入`app`对象：

{* ../../docs_src/app_testing/app_a_py310/test_main.py hl[3] *}

...然后测试代码和之前一样的。

## 测试：扩展示例 { #testing-extended-example }

现在让我们扩展这个例子，并添加更多细节，看下如何测试不同部分。

### 扩展后的 **FastAPI** app 文件 { #extended-fastapi-app-file }

让我们继续之前的文件结构：

```
.
├── app
│   ├── __init__.py
│   ├── main.py